The invention relates to a magnetic head for recording, reproducing and/or erasing magnetic information in a track of a magnetic information carrier. A magnetic core has two core limbs formed from a ferrite, at least one limb having a cladding layer of a magnetic material having a higher saturation magnetization than the ferrite. A non-magnetic gap is present between the core limbs and a winding aperture having an electric coil is wound around at least one of the core limbs.
A magnetic head of this type generally denoted in the literature as a MIG head (Metal-in-gap head) is known from the publication IEEE Transactions on Magnetics, Vol. Mag. 18, No. 6, November 1982, metal-in-gap record head, by F. J. Jeffers c.s..
It is generally known to use ferrites, particularly monocrystalline Mn-Zn ferrites as magnetic core materials for magnetic heads because ferrites have a number of advantages. Such advantages are a high resistance to wear, a relatively high specific resistance and satisfactory magnetic properties relating to coercive force and permeability.
Magnetic fields which are generated by a magnetic head at the area of the transducing gap in order to write information on a magnetic medium are directly dependent on the saturation magnetization of the material of the magnetic head core. Ferrites have a saturation magnetization which is sufficiently high to write information on conventional tapes such as CrO.sub.2 tapes having a coercive forceH.sub.c of approximately 700 Oersted. In order to record information on magnetic tapes having a high coercive force such as MP magnetic tapes based on pure Fe, conventional magnetic heads which exclusively have ferrite on either side of the transducing gap are less suitable. The magnetic fields which are generated by such magnetic heads to write information on a magnetic medium are in fact limited by the relatively low saturation magnetization of the ferrite. The strength of the writing field is therefore insufficiently high to ensure optimum writing of magnetic tapes having a high coercive force.
A stronger writing field is envisaged with the magnetic head known from the said publication. This known magnetic head has sendust cladding layers. These soft magnetic layers are present on either side of the non-magnetic gap and are provided by sputtering on the core limbs connected together by means of a glass joint. The gap is composed in a manner not further described.
It is to be noted that a cladding layer may consist of a plurality of layers provided on one another as has already been proposed in the non-prepublished Dutch patent application 8601732, to which U.S. application Ser. No. 018,686 (now abandoned) corresponds, herewith incorporated by reference.
A similar magnetic head is known from the magazine Journal of Magnetism Materials 54-57 (1986) 1567-1570 "Recording characteristics of high metal powder floppy disc" by H. Fujiwara c.s. The non-magnetic gap consists of a glass layer and two SiO.sub.2 -layers, which SiO.sub.2 -layers extend between the glass layer and the cladding layers. When this known magnetic head is manufactured, the composition of the gap is to be effected at a temperature in the range between 500.degree. and approximately 700.degree. C. due to the glass properties. Such a high composition temperature may, however, have several detrimental effects on the magnetic head provided with cladding layers. One of these detrimental results may be a deterioration of the magnetic properties of the soft-magnetic cladding layers. Furthermore mechanical stresses may be created in the cladding layers at high temperatures, which stresses are so high that they cause fractures in the ferrite core limbs.